ARL syntax

The primary function of an ARL is to direct an end user’s request for an
object to the Akamai network. The ARL also contains the
object’s caching properties.

Example of an ARL

Serial number

Serial numbers balance the distribution of content on the Akamai network.

Important: The serial number
appears in two places in the ARL and should be the same in both fields.

Akamai domain

Non-secure (HTTP) content: a<serial_number>.g.akamai.net.

Secure (HTTPS)
content: a248.e.akamai.net.

Typecode

Indicates to the Akamai edge servers the
type of coherence mechanism to be used for each object. The two most common options are
typecode 7 and typecode
f.

7

Typecode 7 indicates that the Object Data field contains
an Object ID.

When an Akamai
server first caches an object, it creates an identifying entry for the object that
contains the object’s source URL and the Object ID, for example 200201171350 -
www.foo.com/images/logo.gif. If either of these ARL fields changes in a
subsequent request, the Akamai server retrieves
the new version of the object from the origin server.

f

Typecode f indicates that the Object Data field contains
a TTL value.

The TTL instructs the Akamai servers to send a periodic If-Modified-Since (IMS)
GET request to the origin server to verify that the object is still fresh. Valid
values for the TTL are [number][s,m,h,d]. For example: 30s, 15m, 5h,
30d.

Customer code

Identifies the content provider and is used for billing and reporting.

Object data

Serves as a coherence or object-freshness mechanism. Depending on the
typecode, it contains either an Object ID or a TTL.

URL (absolute)

Specifies the origin or source URL of the object. It is the location from
which Akamai servers retrieve the object to cache or
refresh it.

Attention: Any
domain used in an ARL must be registered through the Akamai Domain Validation tool. If the ARL of an object contains an unregistered
domain, Akamai servers will not serve the
object.